1. Field of the Invention
The present invention relates generally to a G-arm X-ray imaging apparatus. More particularly, the present invention relates to a G-arm X-ray imaging apparatus having a C-arm base having bi-planar imaging chains that may be side mounted or centrally mounted.
2. Description of Related Art
It is often desirable to take X-rays of a patient from a number of different positions, preferably without the need for frequent repositioning of the patient. It is preferable that the X-ray apparatus not unduly encumber the space surrounding the patient to enable a physician to treat or otherwise attend to the patient without the need to repeatedly remove and replace the X-ray apparatus. C-arm X-ray equipments has been developed to meet these needs and have become well known in medical art of surgical and other interventional procedures. An example of prior art C-arm equipment is shown in FIG. 1.
C-arm X-ray equipment is smart and flexible in operation, and in its positioning process, which can be reflected from the equipment's number of degrees of freedom of movement. The C-arm gantry is usually mounted so as to enable rotational movement of the arm in two degrees of freedom. Firstly, the C-arm gantry is slidably mounted to the support structure to enable orbiting rotational movement of the C-arm about its center of curvature (Direction marked ‘A’ in FIG. 1). Secondly, the C-arm equipment provides lateral rotation which is a motion rotating along the horizontal axis (Direction B in FIG. 1). In addition, the C-arm equipment also has a up-down motion along the vertical axis (Direction C in FIG. 1), a cross-arm motion along the horizontal axis (Direction D in FIG. 1) and a wig-wag motion along the vertical axis (Direction E in FIG. 1)
Although the C-arm X-ray equipment is smart and flexible in positioning process, it is often desirable to take X-rays of a patient from both the AP & LAT positions (two perpendicular angles), in such situations, the operators have to reposition the C-arm because C-arm configurations do not allow for such perpendicular bi-planar imaging.
For taking the X-rays from different angles at the same time without repositioning the X-ray apparatus, such a configuration is often referred to as bi-planar imaging that allows an object to be viewed in two planes simultaneously. The two X-ray beams emitted from the two X-ray tubes may cross at an iso-center.
Bi-planar imaging may be accomplished in several ways. One way is by using two independent imaging systems, such as two C-arms. U.S. Pat. No. 4,884,293 issued Nov. 28, 1989, to Koyama discloses a dual imaging system with one imaging system being mounted to the floor and the other being mounted to the ceiling. One disadvantage of this system is that, although the C-arms are coordinated, the imaging systems operate independently of one another. Thus the images produced are not coordinated. Another disadvantage of this configuration is that the two C-arms occupy too much space, inconveniencing the operators.
Another configuration for bi-planar imaging is mounting two imaging chains in a ring. U.S. Pat. No. 3,549,885 issued Dec. 22, 1970, to Andersson discloses a dual imaging system with both imaging systems being mounted perpendicularly in a rotatable ring. One disadvantage of the system compared to C-arm system is that the imaging chain only has the orbital rotation ability, but no lateral rotation ability (can be rotated along the ring only).
Another configuration for bi-planar imaging is mounting the two imaging chains onto a G-arm. U.S. Pat. No. 5,095,501 issued Mar. 10, 1992, to Kobayashi discloses a dual imaging system with both imaging systems being mounted perpendicularly in a G-arm gantry. The configuration can get the photos of two perpendicular positions at the same time. While the two imaging system are mounted on the inner circumference of the G-arm gantry, at one aspect larger orbital rotation angle is obtained, but on the other aspect, as we know, the inner space of the gantry is important to both the patient and the operator, so one disadvantage of this configuration is that there is not enough operation space, especially compared to the C-arm configuration.
Another configuration for bi-planar imaging is disposed two C-arm at one base. U.S. Pat. No. 6,104,780 issued Aug. 15, 2000, to Barry Hanover discloses a bi-plane imaging system with the first C-arm is large and disposed on a wheeled base while the second C-arm is smaller and disposed on the first C-arm such that it nests. As with other configurations, the disadvantage is that the operation space is limited because of the two nested C-arms.